The metabolic pathways of chemical carcinogens, generally various aromatic amines, are studied both in animals and in isolated tissues. Metabolites are separated by various techniques such as thin-layer, column, gas-liquid, or high pressure liquid chromatography. Identification is made through physicochemical means such as mass spectrometry, nuclear magnetic resonance and ultraviolet spectra. Interaction of metabolites with cellular constituents is determined. The effect that inhibitors or promoters of the carcinogens exhibit on the metabolic patterns is studied.